Stringing block



April 28, 1964 A. MCAULEY 3,130,958

STRINGING BLOCK Original Filed Feb. 3, 1961 IINVENTOR. 4 7 12 Wed. .Z W Z.

United States Patent Original application Feb. 3, 1961, Ser. No. 87,028. Divided and this application Jan. 22, 1962, Ser. No.

Claims. (Cl. 254134.3)

This invention relates to a stringing block and more particularly to a stringing block for stringing flexible conductor or cable members between poles, as in a power distribution system, Where the poles are provided with pole top pins mounted on the top thereof.

This is a division of my copending United States patent application, Serial No. 87,028, filed February 3, 1961, for Stringing Block.

In many electrical distribution systems, three or four conductors are strung between poles which have one or more cross arms affixed thereto to which the cables are secured. The modern trend in such system construction is to eliminate the cross arms and secure the conductors either to a pole top pin which consists of a pin extending upward from the top of the pole with an insulator at the end thereof, or to a neutral spool which is mounted on a bolt extending from the side of the pole, normal to its length. At the present time, improvised methods using a snatch block or sheave arrangement are used to string the Wires between the poles. The block is usually attached to a side of the pole with a sling rope and has a tendency to swing around the pole when a knotted rope or conductor wire is passed through the throat of the block. These present methods are undesirable because of tangling and damage to the conductors. This is especially true in the case of aluminum conductors, which are easily damaged and which are being used increasingly more in electrical distribution systems.

A principal object of this invention is to provide a new and improved stringing block for stringing conductors or cables between poles having pole top pins mounted thereon which facilitates the conductor stringing operation and eliminates damage to the conductors.

A feature of this invention is the provision of stringing blocks which may be attached directly to a pole top pin, eliminating the necessity of attaching the blocks to the pole.

Another feature is to provide a stringing block for attachment to a pole top pin including a frame carrying a top and bottom roller which define a cable guide section with the frame.

Another feature is that the top roller is removable from the frame to open the cable guide section permitting removal of the stringing block after the cable has been strung and placed under tension between the poles.

A further feature is the provision of a bracket hingedly attached to the frame member of the stringing block and having a pivotal closure member for securing the block to pole top pins of diflerent sizes.

Another feature is to provide an adapter for use with the stringing block when stringing a cable to round tapered pole top pins.

Further features and advantages of the invention will readily be apparent from the following specification and from the drawings in which:

FIG. 1 is an elevational view of a pole top pin stringing block embodying the invention;

FIG. 2 is a plan view of the stringing block of FIG. 1;

FIG. 3 is a perspective view of the stringing block of FIG. 1;

FIG. 4 is an elevational view of the pole top pin string- ICC ing block as attached to a round, tapered pole top pin and utilizing an adaptor;

FIG. 5 is an elevational view of the adaptor;

FIG. 6 is a plan view of the adaptor;

In FIG. 1 a pole 10 is illustrated having a pole top pin 11 mounted at the side thereof by bolts 12 and extending vertically upward beyond the top of the pole. An insulator 13 is provided at the top end of the pin11 for carrying a conductor or cable strung between similar poles of a power distribution system. The pole top pin stringing block is indicated generally at A, and includes a U-shaped frame member 15 having upstanding legs 16 and 17 and a base or bight 18. A pair of bracket plates 20 and 21 extend outwardly from the side edges of and normal to the leg 17. A threaded bolt 22 is hinged at 23 with the edge of bracket plate 21 and engages a slot 25 provided in the edge of bracket plate 20. The leg 17, the bracket plates 20 and 21 and the bolt 22 provide a bracket closure for surrounding pole top pin 11 and a wing nut 26 threaded onto the end of bolt 22 provides a means for tightening the closure about the pole top pin to secure the stringing block A thereto. The bracket plate 21 is rigidly aflixed to one side edge of the leg 17 and the bracket plate 29 is hinged at 27 to the other side edge of the frame leg 17. The hinged bolt 22 and the hinged bracket plate 26 provide flexible adjustment for the bracket closure portion of the stringing block so that the block may be secured to various size pole top pins.

A pin 28 is carried between the legs 16 and 17 of frame 15, parallel and adjacent to the base 18. The pin carries a concave roller 30 which is free to roll thereon and which extends substantially the entire distance between the legs. The roller 30 provides a rolling support for sup porting a cable 31 that is strung between the poles of the electrical distribution system. A threaded pin 32 is hinged at 33 to the top edge of frame leg 17 and carries a top roller 34 which is free to rotate thereon and extends substantially the entire distance between the legs 16 and 17. The roller 43 is carried directly above roller 30 and is parallel thereto. The pin 32 extends beyond leg 16 and engages a slot 35 provided in leg 16 and a wing nut 36 is threaded on the end of pin 32 to secure the pin in slot 35. The top edge of leg 16 is provided with a flange 37 extending at right angles thereto to prevent bolt 32 from becoming disengaged from slot 35 after the wing nut has been tightened. It should be noted that a closed guide portion for the cable 31 is formed, the top and bottom being defined by rollers 34 and 30 respectively, and the sides by legs 16 and 17 of the frame 15.

In using the pole top pin stringing block, the block is easily installed on the pole top 19 by opening the hinged bolt 22, as shown in FIG. 3, and placing the outside surface of leg 17 against the pin 11. The bolt 23 is then engaged in slot 25 and wing nut 26 tightened to firmly secure the block to the pole top pin. Cable ends or ropes attached to the cables are then strung through the guide portion between the rollers 34 and 3t and the cables tensioned between the poles. The Wing nut 36 is then loosened and the bolt 32 carrying the roller 34 pivoted upward as shown in FIG. 3, so that the cable may be removed and tied on the insulator 13. The stringing block is then easily removed by loosening the wing nut 26. In new pole installations, the stringing block may be assembled on the pole top pin and the cables or conductors strung while the poles are still on the ground which further facilitates the operation.

Certain pole top pins are of a round, tapered shape as indicated at 40 in FIG. 4. The round, tapered surface of the pin makes proper positioning of the stringing block difficult and an adaptor 41 is provided to eliminate this difficulty. The adaptor is illustrated in FIGS. 4, 5 and 6, and comprises a rod or heavy wire, as 7 steel rod, bent into a U-shaped configuration having legs 42 and 43 with their ends bent back toward the juncture of the two legs to form hooked portions 44 and 45 in a plane normal to the plane of the U configuration. A curved spreader bar 46 is secured to legs 42 and 43 adjacent the hooked end of the adaptor. The adaptor 41 is placed in position on the stringing block as shown in FIG. 4 with hooked portions 44 and 45 engaging the top edge of frame leg 17 and straddling the roller 34, and the spreader bar 46 resting against the round pole pin 49 with its curved surface conforming to the surface of the pole pin. The lower portion of the adaptor at the juncture of the legs 42 and 43 is bent slightly inward as at 47 to abut the lower portion of the pole pin. The adaptor enables the stringing block to be positioned accurately on a round pole pin since the spreader bar 46 conforms to the surface of the pin and provides substantial surface contact between the pin and the stringing block frame.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications, changes therefore in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

I claim:

1. A stringing block comprising:

a U-shaped frame, having a bight and a pair of parallel,

upright legs;

a first fastener attached to one of the legs at the free end of the latter and spanning the distance between the legs;

means for releasably attaching the first fastener to the other leg; I

a pair of spaced, horizontal rollers spanning the distance between the legs, one of the rollers being journalled on the first fastener; and I clamp means including a pair of spaced plates extending outwardly from said one leg, one of the plates being rigid with said one leg adjacent one upright edge of 1 between the plates, and take-up means for releasably attaching the second fastener to said other plate, whereby when the clamp means is placed on a pole top pin it may be rigidly attached thereto by actuation of the take-up means to draw said one plate toward said other plate thereby gripping the pin between the plates.

2. The invention of claim 1, wherein said other leg is provided with a flange extending outwardly at a right angle from the free end thereof, said flange and free end having a vertical slot therein for receiving said first fastener, the means for attaching the first fastener underlying the flange whereby the latter prevents disengagement of said first fastener from said slot.

3. The invention of claim 1, wherein said one plate is integral with said one leg and wherein said second fastener is swingably attached to the free end of said one plate.

4. A cable stringing device for attachment to a round, tapered, pole top pin comprising:

a frame having an upright leg forming one border thereof, said leg being provided with an upper, free end;

a pair of spaced, horizontal rollers carried by said frame, the rollers and the frame cooperating to define a cable guide section;

a U-shaped adaptor rod having a pair of upright legs, a hook on the free end of each of the adaptor rod legs respectively, and a curved spreader bar spanningthe distance between the rod legs adjacent the hooks thereon, said hooks normally being in hooked engagement with the free end of said frame leg; and

a bracket secured to the frame for attaching the latter to the pole top pin with said spreader bar in mating engagement with the pin and with the rod legs between the pin and said frame leg and abutting the latter whereby, when the bracket is secured to the pin, the rod legs and the spreader bar are sandwiched between the pin and the frame leg to adapt the latter to support the tapered surface of the pin.

5. The invention of claim 4, wherein the extremity of the adaptor rod opposite said hooks is laterally bent for engagement with the pole top pin.

References Cited in the file of this patent UNITED STATES PATENTS 1,168,049 Beck Jan. 11, 1916 1,719,863 Wirz July 9, 1929 2,188,715 Ingram Jan. 30, 1940 2,202,184 Berger May 28, 1940 

1. A STRINGING BLOCK COMPRISING: A U-SHAPED FRAME, HAVING A BIGHT AND A PAIR OF PARALLEL, UPRIGHT LEGS; A FIRST FASTENER ATTACHED TO ONE OF THE LEGS AT THE FREE END OF THE LATTER AND SPANNING THE DISTANCE BETWEEN THE LEGS; MEANS FOR RELEASABLY ATTACHING THE FIRST FASTENER TO THE OTHER LEG; A PAIR OF SPACED, HORIZONTAL ROLLERS SPANNING THE DISTANCE BETWEEN THE LEGS, ONE OF THE ROLLERS BEING JOURNALLED ON THE FIRST FASTENER; AND CLAMP MEANS INCLUDING A PAIR OF SPACED PLATES EXTENDING OUTWARDLY FROM SAID ONE LEG, ONE OF THE PLATES BEING RIGID WITH SAID ONE LEG ADJACENT ONE UPRIGHT EDGE OF THE LATTER, THE OTHER PLATE BEING SWINGABLY ATTACHED TO SAID ONE LEG ADJACENT ANOTHER UPRIGHT EDGE OF THE LATTER, A SECOND FASTENER ATTACHED TO SAID ONE PLATE AT THE FREE END OF THE LATTER AND SPANNING THE DISTANCE BETWEEN THE PLATES, AND TAKE-UP MEANS FOR RELEASABLY ATTACHING THE SECOND FASTENER TO SAID OTHER PLATE, WHEREBY WHEN THE CLAMP MEANS IS PLACED ON A POLE TOP PIN IT MAY BE RIGIDLY ATTACHED THERETO BY ACTUATION OF THE TAKE-UP MEANS TO DRAW SAID ONE PLATE TOWARD SAID OTHER PLATE THEREBY GRIPPING THE PIN BETWEEN THE PLATES. 